Study of the thermal and mechanical properties of local clay materials activated with quicklime, Sefrou (Morocco)

Abstract

This study aims at testing experimentally the stabilization of unexploited clay from the Bensmim region (Middle Atlas, Morocco) using traditional quick lime from Sefrou located nearly to Bensmim for potential use in building applications. The main purpose of the present work is to evaluate the thermophysical and mechanical behavior of lime-stabilized clay blocks. Many different samples of clay specimens reinforced with lime at six different contents (0%, 10%, 20%, 30%, 40%, 50%, and 70%) were prepared and tested. The thermal characterization was made by the Asymmetrical Hot Plate method in study state and transient regime to identify, respectively, the thermal conductivity and the thermal effusivity. The Flash method was used to evaluate thermal diffusivity. The mechanical performance was measured in terms of compressive and flexural strengths. Besides, a Chemical identification of Bensmim clay was investigated via the X-Ray Fluorescence method. Particle size distribution of used clay was determined following a wet sieving analysis method. The results of clay identification showed that Bensmim clay meets the minimum requirements for manufacturing compressed earth and adobe bricks. The thermophysical tests results showed that the lime addition positively influences the lightness and the thermophysical properties of lime-stabilized clay specimens. For the findings of the mechanical tests, it is observed that the flexural and compressive strengths of lime-stabilized clay blocks continue to increase until a lime content of 30%. After this content, the mechanical performances decrease with lime addition, and no amelioration is detected. Therefore, a lime content of 30% represents the optimal lime content for stabilizing Bensmim clay. At this content, the stabilized clay blocks show optimal mechanical performance and improved thermal properties compared to the reference samples. Stabilized clay blocks at 30% lime content present a 14% improvement in bulk density, 13% in thermal conductivity, 12% in thermal effusivity, 20% in thermal diffusivity, 41% in compressive strength, and 10% in flexural strength, compared to unstabilized specimens.